Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
141 PM EST Sun Feb 18 2024

Valid 00Z Mon Feb 19 2024 - 00Z Thu Feb 22 2024

...West and California...
...Particularly heavy snow tonight into Monday on the Sierra
Nevada above about 6500ft...

Days 1-3...

Moisture surge ahead of the next stronger will be
ongoing/increasing this evening and overnight on the LFQ of an
incoming 165kt jet streak across SoCal. Modest/strong PW/IVT
anomalies (90-95th percentiles) will focus into the
northern/central Sierra, where high intensity snow is likely above
~6500ft (2-5"/hr above 8000ft between 06-18Z Mon). Travel may
become difficult to impossible on some of the higher passes.
Pivoting trailing shortwave on the backside of the mean trough
axis will allow for a continued moisture flux into the region into
Tuesday, mostly into the NorCal ranges (e.g., Shasta/Siskiyous).
WPC probabilities for >18" snow through Tuesday afternoon are >50%
above about 7000ft in the Sierra Nevada and the Shasta/Siskiyous.
Upper trough axis finally moves into/through California on
D3/Wednesday, lowering snow levels to around 5500ft as
precipitation nears its cessation. Additional snowfall will still
likely be over 10 inches on the high Sierra Wednesday.

Into the interior West/Great Basin, moisture will continue to
advect inland on SW flow aloft, favoring the Wasatch and Unitas
later on D2 into D3, then starting to get into the northern CO
Rockies as the trough axis punches its way to the Four Corners by
the end of the period. WPC probabilities for at least 8 inches of
snow on Wednesday are highest (>50%) above 8000ft or so.


The probability of receiving at least 0.1" of ice is less than 10
percent Day 1-3.


Fracasso